Diazepam is one of the most frequently prescribed drugs. Its usefulness as a sedative, muscle relaxant and anxiolytic has been well-documented in brief trials. However, the long-term effects of diazepam are not well understood. While it is known that tolerance develops to its sedative effect, it is not known whether the anxiolytic and muscle relaxant effects are maintained over long periods of drug administration. In addition, recent studies suggest that diazepam affects memory and cognitive processes not only after acute ingestion but also when prescribed in therapeutic dosages over prolonged periods of time. The proposed study intends to compare the effects of diazepam (15 mgs. per day) on sedation, muscle relaxation, anxiety, cognitive performance, and memory in an acute dosage experiment and at three and six weeks of continuous drug administration. In addition, the effects of diazepam on highly anxious patients (diagnosed Generalized Anxiety Disorders, DSM III), and "normal" control subjects will be compared. The aim of the study is to examine, simultaneously, the clinical effects (observer ratings and subject self-ratings), performance under laboratory conditions (cognitive performance, memory functioning, critical flicker fusion thresholod, and autonomic responding to mild and severe stress) and correlate them with benzodiazepine serum levels (total serum benzodiazepine levels, diazepam and desmethyldiazepam levels). It is predicted that continuous administration of diazepam leads to tolerance of sedative effects but not of the anxiolytic and muscle relaxant effects. In addition, cognitive and memory impairment will be observed in acute and chronic conditions and will be higher in the anxious than in the control group. Diazepam may improve not only the clinical but also the performance levels of highly anxious subjects; the opposite is expected in normal controls.